The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran) Author Korn, Dieter 286CA4F3-7EBC-4AEF-A66A-B2508D001367 Museum für Naturkunde, Leibniz Institut for Research on Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany. dieter.korn@mfn.berlin Author Hairapetian, Vachik 1AB10F8F-4576-481B-9270-5DCD25110DBB Department of Geology, Esfahan (Khorasgan) Branch, Islamic Azad University, Esfahan, Iran. vhairap@gmail.com Author Ghaderi, Abbas 925F2B42-7326-4461-B2A6-83CB83ECCC63 Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Azadi Square, 9177948974, Mashhad, Iran. aghaderi@um.ac.ir Author Leda, Lucyna 81481AFA-C8EE-4E90-A954-FD0E7987621E Museum für Naturkunde, Leibniz Institut for Research on Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany. lucyna.skorpion3@wp.pl Author Schobben, Martin 44C2A45A-B16C-434F-8F22-FC9C0FCA2551 Utrecht University, Department of Earth Sciences, Princetonlaan 8 A, 3584 CB Utrecht, The Netherlands. & Department of Geology, Esfahan (Khorasgan) Branch, Islamic Azad University, Esfahan, Iran. schobbenmartin@gmail.com Author Akbari, Amir 3C9DB6F9-2034-418F-876C-49359D07D29F Department of Geology, Esfahan (Khorasgan) Branch, Islamic Azad University, Esfahan, Iran amakbari80@yahoo.com text European Journal of Taxonomy 2021 2021-10-27 776 1 106 journal article 3782 10.5852/ejt.2021.776.1559 453c885c-f427-4a38-ab97-dc14b686e126 2118-9773 5604715 226B6C59-8620-4A29-9BEF-359BE67A1A2C Lutites lyriformis Korn & Hairapetian gen. et sp. nov. urn:lsid:zoobank.org:act: 3FC3DB4D-AA14-43A6-B982-0137ED22D6B7 Figs 51–52 ; Table 26 Diagnosis Species of Lutites gen. nov. with conch reaching 140 mm dm. Subadult stage with parallel-sided, compressed whorl profile (ww/wh = 0.60–0.70) and rounded venter; about 14 ventrolateral nodes per volution. Adult stage with subtrapezoidal, compressed whorl profile (ww/wh =0.50–0.60), concave flanks, concave venter and angular ventrolateral shoulder; numerous weak and densely arranged ribs. Prongs of external lobe bifid to multiply serrated; altogether 13–22 notches of E, A and L lobes. Etymology From the Latin ‘ lyra ’, referring to the shape of the whorl profile. Material examined Holotype IRAN • Esfahan Province , Baghuk Mountain A section ; Hambast Formation; illustrated in Fig. 51A ; MB.C.29995 . Paratypes IRAN • 1 specimen ; Esfahan Province , Baghuk Mountain 1 section ; Hambast Formation ; MB.C.29994 • 2 specimens ; Esfahan Province , Baghuk Mountain C section ; Hambast Formation ; MB.C.29996 to MB.C.29997 • 1 specimen ; Esfahan Province , Baghuk Mountain E section ; Hambast Formation ; MB.C.29998 • 1 specimen ; Esfahan Province , Baghuk Mountain G section ; Hambast Formation ; MB.C.29999 • 2 specimens ; Esfahan Province , Baghuk Mountain H section ; Hambast Formation ; MB.C.30000 to MB.C.30001 . Fig. 51. Lutites lyriformis Korn & Hairapetian sp. nov. , lateral and dorsal views. A . Holotype MB.C.29995, section A, float. B . Paratype MB.C.29997, section C, -1.00 m. C . Paratype MB.C.29996, section C, -1.45 m. D . Paratype MB.C.29999, section G, -1.20 m. Scale bar units =1 mm. Description Holotype MB.C.29995 is a rather well-preserved specimen with 96 mm conch diameter ( Fig. 51A ). It allows the study of three and a half volutions, of which only one third of a volution belongs to the body chamber. Adulthood is indicated by the weak crowding of the last septa at 73 mm diameter. The whorl profile is, at the largest preserved conch diameter, subtrapezoidal with a broadly rounded umbilical margin and concave and converging flanks. The weakly concave venter is separated from the flanks by an angular ventrolateral shoulder. Half a volution earlier, the venter is plane and another half a volution back, the venter is broadly rounded. The sculpture shows significant ontogenetic changes from the subadult stage with 13 coarse and blunt ventrolateral nodes, which originate from weak and rounded radial ribs, per volution. They become weaker and more numerous in the last quarter volution of the phragmocone (about 12 weak ventrolateral nodes within this interval). The body chamber possesses a very weak sculpture consisting only of weak and rounded radial riblets in the inner flank area. The suture line of the holotype possesses a parallel-sided external lobe with prongs being asymmetrically serrated by four and five small notches, respectively. The asymmetric ventrolateral saddle is nearly as wide as high; it is followed by an adventive lobe with oblique base serrated into seven small notches. The weakly asymmetric, inverted U-shaped lateral saddle is nearly as high as the ventrolateral saddle. Finally, the asymmetric lateral lobe has also seven small notches ( Fig. 52A ). The smaller paratype MB.C.29997 has 74 mm conch diameter, of which the phragmocone has a diameter of 64 mm and one quarter of a whorl belongs to the body chamber ( Fig. 51B ). The whorl profile is subtrapezoidal with concave, converging flanks and the venter is weakly concave. The sculpture generally resembles the holotype , but the ribs and nodes are weaker. The same is true for the additional Fig. 52. Lutites lyriformis Korn & Hairapetian gen. et sp. nov. A . Suture line, holotype MB.C.29995, at 58.3 mm dm, 23.1 mm wh. B . Suture line, paratype MB.C.29997, at 53.8 mm dm, 19.0 mm wh. C . Whorl profile proportions. Abbreviations: see Material and methods. Scale bar units =1 mm. Table 26. Conch dimensions (partly estimated) and ratios of selected specimens of Lutites lyriformis Korn & Hairapetian gen. et sp. nov. from Baghuk Mountain.

Specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZR
MB.C.29995	95.8	19.9	34.6	35.8	31.7	0.21	0.58	0.37	2.23	0.08
MB.C.29996	94.3	18.6	31.1	41.3	30.0	0.20	0.60	0.44	2.15	0.03
MB.C.29998	79.7	18.3	26.6	31.3	24.4	0.23	0.69	0.39	2.08	0.08
MB.C.29999	79.2	18.0	28.6	29.3	25.5	0.23	0.63	0.37	2.18	0.11
MB.C.29997	74.3	16.8	25.3	30.1	24.5	0.23	0.66	0.41	2.23	0.03
MB.C.29994	72.0	15.1	24.4	29.2	23.0	0.21	0.62	0.41	2.16	0.06
MB.C.29995	95.8	19.9	34.6	35.8	31.7	0.21	0.58	0.37	2.23	0.08

paratypes MB.C.29996 ( Fig. 51C ) and MB.C.29999 ( Fig. 51D ), which is the conch geometry are nearly identical with the holotype . The suture line of paratype MB.C.29997 shows a parallel-sided external lobe that is deeper than the adventive lobe. The prongs are bifid and parallel-sided. All lobes and thus saddles are parallel-sided and all saddles have the same height. The adventive lobe and the lateral lobe possess six and four small notches ( Fig. 52B ). Remarks The new species differs in the coarse ventrolateral nodes of the subadult stage from most of the other species of Lutites gen. nov. with compressed whorl profile. Lutites lyriformis gen. et sp. nov. is similar to L. profundus gen. et sp. nov. but differs in the much weaker sculpture of the terminal body chamber, which shows only very weak ribs in L. lyriformis gen. et sp. nov. but ventrolateral nodes in L. profundus gen. et sp. nov. Stratigraphic range Upper part of the Hambast Formation; 1.45 to 1.00 m below the extinction horizon ( Lutites profundus Zone to Abichites abichi Zone ).